Degradative polyolefin composition

ABSTRACT

POLYPROPYLENE COMPOSITION WITH ADDED ALDOL-ALPHANAPHTYLAMINE SO AS TO FACILITATE DEGRADATION.

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United States Patent O US. Cl. 260--93.7 3 Claims ABSTRACT OF THEDISCLOSURE Polypropylene composition with added aldol-alphanaphthylaminewas to facilitate degradation.

CROSS-REFERENCES TO RELATED V APPLICATION This application is acontinuation-in-part of United States Ser. No, 778,762, now abandoned.

BACKGROUND OF THE INVENTION Eieldof the invention This invention relatesto a polyolefin composition having a degradative nature whosedecomposition is accelerated under natural environment condition.

Polypropylene or a composition obtained by admixing anotherthermoplastic resin, rubber, an inorganic filler or the like withpolypropylene as the principal component have been consumed in largeamounts for the production of various kinds of, shaped articles such asvessels, general merchandise, films for packaging use, rope, thread andfibers.

The polypropylene used for these purposes must have stability. On thisaccount, there has been an attempt to increase durability by addingvarious kinds of stabilizers.

However in some application fields e.g. in the application field ofbinding tapes used in agriculture and mowing machines for rice plants,it has been found necessary that these tapes be degradatcd anddecomposed after being used in order that the natural environment is notspoiled and so that the operational efficiency is thereby improved.

Accordingly, it is an object of the present invention to provide apolypropylene composition which is sufficiently stable until it is usedbut which after use has such inferior weathering properties that it isreadily decomposed under natural environmental conditions mainly by theaction of SUMMARY OF THE INVENTION The present invention involvesincorporating aldolalpha-naphthylamine in polypropylene or in acomposition containing polypropylene as the principal component togetherwith another thermoplastic resin rubber, inorganic filler orthe like.'Inother words it has been found by "the'present inventors that degradationof polypropylene compositions. particularly by the action of actiniclight, isremarkably accelerated because of such incorporation. f

Aldol-alpha-naphthylamine is a compound represented by the formula3,642,761 Patented Feb. 15, 1972 (M.P. 60 C., available from the marketas a resinous product with a trade name Noclack A., Supplier: OuchiShinko Kagaku Kogy KK. and Kawaguchi Kagaku Kogyo K.K.)

or by the formula NICHCHZCHOI'ICHS (M.P. 140 C., available from themarket as a powdered product with a trade name Noclack C., Supplier:Ouchi Shinko Kagaku Kogyo K.K. and Kawaguchi Kogyo- These compounds havebeen known as remarkably useful antioxidants in rubbers. It istherefore, a quite surprising fact that these materials give degradativeaction to polypropylene and compositions obtained by admixing anotherthermoplastic resin, rubber, inorganic filler, etc. with a principalcomponent of polypropylene.

There is no limitation as to the amount of aldol-alphanaphthylaminewhich can be added to polypropylene. The amount is usually controlledadequately according to the purpose but the addition of at least 0.01%is necessary. It is desirable from an economical viewpoint that themaximum amount of addition is less than 3.0%, and preferably 1.0% orless.

As for the resin used, polypropylene is its principal component but itis possible to mix 35% or less by weight of another resin based upon thetotal weight of the composition or 40% or less by weight of an inorganicmaterial based upon the total weight of the composition with theprincipal component polypropylene.

Illustrative other thermoplastic resins and rubbers which can be mixedwith the polypropylene, include low density and high densitypolyethylenes, polybutene-l, poly-4- methylpentene-l, ethylene-vinylacetate copolymer, butyl rubber, polyisobutylene, and butadiene rubber.

Illustrative inorganic fillers include talc, asbestos, calciumcarbonate, etc. These fillers are used, of course, in the form of finepowder.

The polypropylene used herein implies the homopolymer of propylenecontaining at least crystalline part and the block copolymer ofpropylene and ethylene containing a propylene segment or propylenesegments and an ethylene segment or ethylene segments or anethylenepropylene random copolymer segment or ethylene-propylene randomcopolymer segments the ethylene content of which block copolymer is lessthan 35%.

As for the method of mixing the components, any of the conventionalmethods can be used. For example powdered polypropylene and otherpowdered components are blended in a blender, or pelletized otherthermoplastic resin and polypropylene are mixed by melting in anextruder to produce pellets or polypropylene and one of various kinds ofrubbers can be mixed by milling in a mixing roll so as to produce asheet form which can be followed by cutting into pellets.

The following examples are given to illustrate the compositions of thepresent invention but it is to be understood that they are not for thepurpose of limitation. All percents herein are by weight.

Example 1.Compositions prepared by adding each 0%, 0.05%, 0.1% and 0.2%of commercial aldol-alphanaphthylamine (Noclack C supplied from OuchiShinko Kagaku Kogyo K.K.) to commercial polypropylene (brand No. 1066supplied from Chisso Corporation) were extruded and stretched intobinding tapes having a width of 42 mm. and a thickness of 33,41.(approximately 11,600 denier). These tapes were subjected to aweathering test with a weatherometeer WE-SH-2C type made by Examples4-12.To commercial polypropylene (brand Toyo Rika Kogyo (two carbon arctype, panel tempera- No. 1016 supplied from Chisso Corporation), 0.3% ofture; 75 0., room temperature; 50 0, relative humidity; commercialaldol-alpha-naphthylamine (Noclack C, sup- 56%, kept rainy condition for18 minutes per 120 plied from Ouchi Shinko Kagaku Kogyo K. K.) and aminutes) 5 resin or an inorganic filler described in Table 4 were Theresults are summarized in Table 1. added to prepare a cord having awidth of 40 mm. and

TABLE 1 Irradiation for 140 hours Durability Initial elonga- Elonga-Elenga- Amount of Noclack strength, tion, Strength, tion, Strength,tion,

0 added, percent kg. percent kg. percent kg. percent After 160 hrs.exposure the composition in which 0.2% of Noclack C was incorporatedbecame brittle and crumbled and was in a state in which testing ofstrength v and elongation was no longer possible. a thickness of 30p.This cord was subjected to an ultra- Example 2.The compositions preparedby adding violet ray-irradiation for 140' hours by means of 'a each 0%,0.05%, 0.1% and 0.2% of a commercial aldole -O-meter, WE-SH-ZC Typ m yToyo Rika alpha-naphthylamine (Noclack c) to a mixture of 90% Kogyo(carbon are two l p typ la k panel commercial polypropylene (brand No.1066 supplied mp r 75 room temperature, relative from ChissoCorporation) and 10% of commercial low humidity, and 18 minutes during120 u density polyethylene (brand No. F 222 supplied from rainy) tomeasure the strength. The figures shown in Ubekosan K. K.) were extrudedand stretched into bind- Table 4 are the strength retension degree ofthe samples ing tapes 42 mm. wide and 32p. thick. After the outof theexamples expressed by percentage wherein those door exposure for about18 days starting from Aug. 1, in the case of non-irradiation are made100. 1967 in the city of Ichihara, Chibaken, Japan, the reductions ofthe strength and elongation were as listed in Table 2.

TABLE 2 After 10 days After 18 days Initial Initial elonga- Elonga-Elonga- Amount of Noclaek strength, tion, Strength, tion, Strength,tion, added, percent kg. percent kg. percent kg. percent 15 4s 17 52 1s44 17 as 12 23 7 41 14. 30 10 17 5 44 14 28 0 17 5 From about the 24thday, the compositions contain- TABLE 4 ing 0.2% of Noclack fell intotatters. 40 st th ren Example 3.Comrnerc1al polypropylene (brand N0. gia f a e y 1014 supplied from ChlSSO Corporation) was milled on ExampleAdditive percent g gef rolls at 180 C., and 0%, 0.2%, 0.4%, 1.0%, 2.0%and 4 LD E 3.0% of commercial adol-alpha-naphthylamine (Nor g g gg clackA or C supplied from Ouchi Shinko Kagaku Kogyo 1u t 1 r bpe nuu 2O 18 K.K.) was added thereto, subjected to milling for 7 31:: g g g g fi g g8 5es os pow ers 20 minutes and shaped into sheets 1 mm. thick by pressingi? ,gfi i g y d 10 o 2 aoumear one. epow ers 40 14 w1th a heating pressat 200 C. under 200 kg /crn. for r5 Silica powders n 10 21 o d 5 mmutesN 0'rE.LDPE: Low density polyethylene (MI: 12.0); HDPE: High Theresultant sheets were subjected to irradiation bydensitypolyethylene(M1280);ButylrubberzPolysarButyllol u liad fromPolymer Corp.; Polyisobutylene: Vistanex L-80 supplied from the use ofthe same weatherometer as that of Example 1 Eniay Chem. 00.; Butadienerubber: Diene 35A supplied from Asahi and the irradiation time whichelapsed till bending at KaseiKOgyo 135 to give breakage was tested. 0Example 13.-0.3% of aldol-u-naphthylamine as in Ex- The result is Shownin Table amples 4-12 was added to an ethylene-propylene, copolymercontaining 32% of ethylene unit, and a similar test to those of Examples4-12 was carried out. Asa result,

the strength retention degree was 23% in contrast to a controlcontaining no aldol-u-naphthylamine.

TABLE 3 Example 14.-0.3% of aldol-a-naphthylamme as in Ex- Amount of 5 23 Amount of 533 amples 4-12 was added to a block copolymer of propyleneNoclack A 1mm Noclack 0 mm and ethylene containing a propylene segmentand an ethfi g ggggg ylene-propylene random copolymer segment theethylene content of WhlCl'l block copolymer 1s 5%, and a s1milar 28 3 28test to those of Examples 4-12 was carried out. As a 40 0.4 40 result,the strength retention degree was 17% in contrast g8 $8 to a controlcontaining no aldol-a-naphthylamine. 20 3. 0 20 Example l5.0.3% ofaldol-a-naphthylamine as in Examples 4-12 was added to a block copolymerof propylene 5 and ethylene containing a propylene segment and anethylene segment the ethylene content of which block copolymer is 15%,and a similar test to those of Examples 4-12 was carried out. As aresult, the strength retention degree was 20% in contrast to a controlcontaining no aldol-a-naphthylamine.

LAS evident from the foregoing examples it can be seen thatpolypropylene and compositions obtained by admixing anotherthermoplastic resin, rubber, an inorganic filler or the like withpolypropylene as main component, lose their strength, elongation andtoughness under natural environment condition, particularly under theaction of actinic ray by the addition of aldol-alpha-naphthylamine andhence are desirous when they are to be used as binding tapes foragricultural use, particularly for mower of rice plants.

What is claimed is:

1. A composition comprising a propylene containing polymer or copolymerand about 0.'01-1.0% by weight of an aldol-u-naphthylamine, whereby saidaldol-a-naphthylamine renders said propylene containing polymer orcopolymer more readily degradable under natural environmentalconditions.

2. A composition according to claim 1 wherein said aldol-a-naphthylaminehas the formula:

3. A composition according to claim 1 wherein saidaldol-ot-naphthylamine has the formula:

III=CHCH2CHOHCH3 References Cited U.S. patent application Ser. No.778,762; Fukuichi et 211., filing date Nov. 25, 1968.

20 JOSEPH L. SCHOFER, Primary Examiner W. F. HAMROCK, Assistant ExaminerU.S. Cl. X.R.

25 26041, 88.2 S, 94.9 GB, 897, 879

